1. Field of the Invention
The present invention relates to a heat sink having excellent heat dissipation by convection, which is used for heat generating parts applied to motors for electric vehicles, control circuits therefor, internal combustion engines, general power control units, various types of motors, various types of semiconductors (CPUs, power modules, etc.), optical semiconductors, and other various electric and electronic components, etc.
2. Description of Related Art
Effectively cooling heat generating parts of the above-mentioned electric and electronic components, etc. is an important problem to be solved when using equipment. Also, a cooling system for the heat generating parts is required to be small in size.
Conventionally, the heat generating parts of the electric and electronic components, etc. have been cooled by thermally connecting a heat sink of aluminum or aluminum alloy to the heat generating part. However, because aluminum or aluminum alloy (hereinafter both are described as aluminum alloy) has a low thermal conductivity, heat diffusion by the heat sink is insufficient. Thus, a sufficient cooling effect cannot be obtained. This problem has so far been solved by making a large-sized heat sink.
For example, U.S. Pat. No. 3,566,959 discloses a heat sink of an extruded section provided with many fins for a semiconductor rectifier assembly.
However, the heat generating parts have been made small and the calorific value has increased, hence a heat sink having higher performance and smaller size has been in strong demand.